This proposal has as its objectives an understanding of synthesis and degradation of low molecular weight proteins. In particular, beta 2-microglobulin an immunoglobulin related protein will be studied with regard to its lymphoid origins, altered synthesis in neoplastic conditions, its potential role in cell-mediated immunity, and the mechanism of its renal tubular catabolism. Differential metabolism of beta 2-microglobulin, immunoglobulin light chains, and lysozyme will be investigated for potential value in assessing success of renal homotransplantation and renal dysfunction in multiple myeloma.